This invention is a device that permanently attaches to the electrical plug of an appliance and requires a key in order to permit power to be delivered to the appliance. Such a device restricts operation of an electrical appliance so that only authorized persons with a key may allow the appliance to be used. A typical home use of the device would be to attach it to a television so that a parent with a key to the switch can regulate when the television may be operated by the children.
However, the present invention may also be employed in the workplace where access to certain electrical appliances needs to be restricted The unauthorized use of photocopiers outside of business hours may be prevented by opening the key activated switch and removing the key. Similarly, the use of computer time, which may be very expensive, can be regulated by employing the present invention if the computer is permanently attached to its power supply line. While passwords in a computer system present a hurdle to the unauthorized access of data, the present invention prevents the exposure of the password to potential violators.
Many devices for locking electrical plugs exist in the prior art. Some of these devices lock electrical plugs into electrical receptacles. U.S. Pat. No. 4,479,688 to Jennings discloses a wall outlet lock device The device has a cover that locks over a plug that is plugged into the wall outlet device. One lock secures the cover to the apparatus so that the plug cannot be removed. A key-operated switch controls the flow of power to the device so that use of the device plugged in can be regulated. One feature of this device is that it locks the plug to the wall so that the appliance cannot be removed. In this way, the device prevents theft. However, because of the potential fire hazard, universal housing codes presently restrict the locking of electrical devices into wall outlets.
This device has another major disadvantage. Because the device is attached to the wall outlet, the device cannot be transported with the appliance while the plug is locked in. Thus, one cannot move the appliance to be locked without installing another device at another location. For example, if a parent wished to limit the use of a portable stereo by children, the parent can only regulate the use of the portable stereo only if it remains in the one location where the device has been installed. The parent can move the portable stereo to another location and still restrict its use only if the parent has another device installed. This can be a real problem, especially if the appliance is one that is moved often.
U.S. Pat. No. 4,080,029 to St. Fort discloses a plug lock device. The device locks a plug into a wall outlet and requires a key to release the plug from the outlet. The device prevents anyone without a key from removing the plug .from the outlet and thus can prevent theft. However, the device has no means for regulating the flow of power to the appliance. Thus, the device cannot be used to prevent unregulated use.
U.S. Pat. No. 3,345,603 to Cohen discloses an electrical plug key lock device similar in operation to the St. Fort device. The device allows the plug to be locked into a wall outlet. The plug can only be removed by unlocking it with a key. The device, however, is only capable of preventing accidental and intentional removal of an appliance plug from a receptacle. Consequently, the device does not provide any means for regulation of the flow of power to the appliance so it can not be used to restrict use of an appliance.
Although there are many plug lock devices in the prior art, none satisfy the need for the regulation of power supplied to an appliance by a device that permanently attaches to the appliance and not to the wall. In addition, a further serious disadvantage of the prior art is that many devices in the art violate housing and building codes because the devices permanently attach to wall outlets. There is a great need for a device that attaches to an appliance and allows the use of the appliance to be regulated.